<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>表单标签</title>
	</head>
	<body>
		<form>
			<table border="1px" cellspacing="0" bgcolor="gainsboro">
				<tr>
					<td colspan="2"> <!-- 合并列 -->
						<h2 align="center">注册表单</h2> <!-- 居中-->
					</td>
				</tr>
				<tr>
					<td>用户名：</td>
					<td>
						<input type="text" placeholder="请输入用户名"/>
					</td>
				</tr>
			</table>
		</form>
	</body>
	</body>
</html>
